Simple test is turn the carb upside down and gently blow down a pipe connected to each fitting - the actual inlet shouldn't allow air to pass, the return will. A restrictor should be fitted to ensure there is pressure against the float valve otherwise the fuel takes the 'path of least resistance' and takes the bypass back to the tank.

Yes and no LOL! The seat position lever is slightly different but the mechanisms are identical and can be swapped. BUT the Recaro seats require an additional bracket between the seat and the mechanism to mate the two together. The brackets are really simple but rare as a rare thing on Ebay and suchlike sites!

It may be but its boarderline IMO - 1.4kw starter will pull 117A @ 12v (more if v. cold) add ignition, coil, fuel pump, odd small electrics - say 20A? and you are up to 140A ish - if you derate the cable due to additional length to 150A capacity, it wouldn't take much more (like lights being on) to warm up the cable. 16mm2 cable is rated at 110A and is 8.5mm dia, 25mm2 cable is rated at 160A and is 10.1mm dia - I was being cautious on rating.
Modern cars often have main cable fuses but their electrical loads can almost equal what our older cars draw on starter alone - you'd probably have to 'stall' the starter to pop a fuse due to overload - I don't like the idea of a fuse so i'd rather use a battery cut off isolator (good chancer anti theft measure with key removed). I used 240A rated cable in mine which has sufficient excess capacity if I wanted to add a power steering kit - they draw 40A alone.

Your battery + cable does sound a bit undersized - ok if the battery was close to the starter but you've added 12 feet of additional resistance. It sounds like the cable is rated at about 160A and your starter will drag about 100 - 110A so not a lot of excess capacity over the long run. I'd be inclined to replace the cable with some rated at 240A / 12mm dia. Regarding the earthing situation - I wouldn't worry about earthing the gearbox. I'd make sure i've got a decent cable from battery to body in the boot, another from starter mount bolt to body and another from somewhere else on the engine to the body - good earths are essential for reliable starter operation.

True - but they owned / operated multiple 'identical' cars and there was no attempt to defraud anyone. To anyone outside the 'rally world', the cars were identical and handy when you registered a series of consecutive reg. numbers each year.

Probably not! If its been dormant for more than a few years then it'll attract an inspection and if its a left hooker on a UK plate = hello fraud squad, DVLA rubber glove brigade! I think the DVLA are sick of helping the fruadsters and ringers - only taken best part of 30 years!

If it ain't why did they pick the 40 year cut off when the Euro requirement was 30 years ? What the betting the info will be shared as effectively the substantially modified phrase will be used across both for tax and MOT reasons - call me cynical - ABSOLUTELY!

When the 'booked in' MOT started a few years back the 'men in black' mandated a set inspection time - once started the tested couldn't register another test on the system until the time was up - if you wanted more throughput, you needed more testers. I think the time was 45 minutes and bikes 25 or 30 minutes. When you work it back against labour rates they are loss leaders - a service that hopefully is tacked onto a workshop service or repair that does make some money - they hate thing that pass 1st off!

Playing with cars is the same as any speculation - don't risk what you can't afford to lose ! Tying up your 'life savings' in a car is really risky in any instance unless its bone stock, desirable and rare. Otherwise, you do it because you want to and hope that you get some money back if it comes to crunch time! I devalued mine as soon as I got it by adding efi and a zetec but I also got rid of a lot of sh1te that was on it - overall it's a better car but not a 'pure blood' and its had a history - so what I get if I sell, is what I get on the day - I have nothing invested that I wouldn't lose sleep over!

Across the whole of the Classic car world there is a lot of speculation as to what is going to happen. This change is Euro law and the civil servants have tied this into the 40 year tax rules for 'historics'. To claim exemption you have to confirm there are no substantial modifications - if you don't claim exemption you have to MOT but i'm guessing you'll also lose the tax benefit as well BUT as tax is Customs and Excise and MOT is DVLA they are entirely unrelated so anything is possible! Also if you claim exemption 'falsely' it potentially lays you open to a snap inspection by DVLA just to check - you can imagine the aggro you'd get if you'd been naughty - not talking naughty step for an hour either!

If it was me, i'd put the pump below the tank and outside the boot for a couple of reasons - a). pumps like to push fuel although they can lift if height of lift is small and b). tank exit is outside and pipe run to engine bay is outside, so why bring it inside and then back outside and c). any potential fuel leaks ( gravity / under pressure) are best outside rather than inside IMO!

Basic theory is if the coil is 12v normally, the additional load from the starter drags the voltage down lower than 12v. which degrades the spark, so if a 9v coil is fitted, whatever the voltage drops to - it'll generally be higher than its required running condition so giving a bigger spark - helpful with cold starting. A 9v coil can take constant 12v but its life will be shortened.